The present invention relates to a novel rifamycin derivative or salts thereof, a process for preparing the same and antibacterial agents containing the same as an effective ingredient. More particularly, the present invention relates to a novel rifamycin derivative having the formula (I): ##STR3## wherein A is a group having the formula: ##STR4## in which R.sup.1 is an alkyl group having 4 or 5 carbon atoms or an alkenyl group having 3 to 5 carbon atoms, or a group having the formula: in which n is 3 or 4; or a salt thereof, a process for preparing the same and antibacterial agents containing the rifamycin derivative or a pharmaceutically acceptable salt thereof as an effective ingredient.
The rifamycin derivative of the present invention is a novel compound which has not yet been reported in the literature.
For the purpose of developing a novel superior antibacterial agent, the present inventors have synthesized a novel rifamycin derivative having the formula (I): ##STR5## wherein A is as defined above and investigated the antibacterial activity and pharmacological characteristics thereof, and as a result, found that the novel rifamycin derivative having the formula (I) exhibits a strong antibacterial activity and excellent pharmacological characteristics.